A conventional millimeter wave bands semiconductor package, on which a semiconductor chip operating in such a millimeter wave bands of 30 GHz or higher is mounted, includes a base body on which the semiconductor chip is placed, a signal line in which one end thereof is connected to the semiconductor chip and the other end acts as an antenna, and a cover body which is provided on the base body to cover the semiconductor chip. Such a conventional millimeter wave bands semiconductor package is used by inserting the signal line into a waveguide which is connected to an external electrical circuit or the like.
However, the conventional millimeter wave bands semiconductor package which was disclosed in Japan Patent Number 3485520 has two waveguide blocks for an input terminal antenna and an output terminal antenna. Since the two waveguide blocks are separate components, the installation states of the waveguide blocks for the antennas are changed at each terminal antenna. Accordingly, there is a problem in that the millimeter wave bands semiconductor package and a millimeter wave bands semiconductor device in which the semiconductor chip is mounted on the package are poor in reproducibility.